Fuse or cut-out



C. E. LEONARD FUSE OR CUT-OUT Oct. 24, 1933.

Filed May 31. 1932 INVENTOR.

cups/me t Ea/M120 BY v 1 l ATTORNEY.

Patented Oct. 24, 1933 UNITED STATES PATENT OFFICE .FUSE 0R CUT-OUT Clarence E. Leonard, Grosse Pointe, Mich.

6 Claims.

My invention relates to a new and useful improvement in a fuse or cut out adapted for being interposed in the line of an electric circuit and to serve as a. safety or cut out in the circuit.

It is an object of the present invention toprovide a fuse of a permanent nature so that when the fuse has blown the same may be very easily and quickly removed or again rendered operative.

It is another object of the present invention to provide a fuse of this class in which the fusible or cut out portion is formed from a comparatively stable liquid conductor such as mercury or'the` like,l and' in Which the column of liquid may bey easily and quickly restored When once the electrical connection has been broken.

Itis anotherl object of the present invention to provide. in a fuse of this class a structure having a supplyA reservoir or chamber at one end and av capillary tubev and an overflow reservoir or chamber at the other end so that.. While the mercury or other liquid used may Ybe easily and quickly forced into the. capillary tube for establishing the necessary electrical conection, nonev of the. liquid` will be Wasted becauseof an overflow .or an overash when` a heavy load comes; upon the line. j

Another object of theA present inventionY is the provision in a fuse of this class of a. capillary tube having a column of electrical conductingV liquid therein and provided with means4 for maintainiugVH the electric circuit even. when the column of liquid may shrink..

g, Another'object of the invention is the provision ofi a fuse of this class. adapted. and arranged for use glass retainers or in screw sockets.4

.Anotl'ierV object of the invention is 'the' provision in` a, fuse of this class of' a construction whereby the, capillary tube may befilled with column of electric conducting liquidY free from oxides and other impurities,

ill-neither object of the: invention is the pro vision ina fuse of this class of .a structure whereby a spilling of the liquid from the capillary tube will be reduced to a minimum.

Another object of the invention is the provision of a structure whereby thevoverflow liquid may lee returned to the initial supply reservoir or chamber. l

Another object of the invention is the provision of a fuse of this classY which will be simple in. structure, economical of manufacture, durabla compact, highly efficient in use, easily Vandquiclrly assembled, ,and easily and. quickly installed in position for use.

Other objects will appear hereinafter.

The invention consists in the combination and arrangement of parts hereinafterdescribed and claimed.

The invention Willi'be best understood by a w reference to the accompanying drawing which forms a part of this specification, and in which,

Fig. 1 is a central, longitudinal, sectional view of the invention.

Fig. 2 is a sectional View taken on liner 2 2 g5, of Fig. 1. l Fig. 3 is a fragmentary sectional View of a modified form of a capillary tube used inthe invention.

Fig. 4 is a centralsectional View showing an 79 application of the invention to a screw socket.

Fig. 5 is a central sectional View of a further adaptation of the invention for use in a screw socket. 1 y

Fig. 6 is anv end elevational View `of the form 75 shown in Fig. 5.

In the invention I provide -a main body l formed from glass or other suitable transparent insulating material. Secured to the opopsite ends of the body '7, so as` to close the same, are the 80 metallic cup-shaped plates or caps 8 and 9, the plate 9V having the vent opening 10 formed therein. Fixedly mounted Within the body 7, intermediate its ends, is the partitionv 11 of insulating material. Mounted-in the body 7 at 85 one side thereof so as to extend axially thereof and project beyond the opposite sidesl of the partition 11 is a capillary tube Y12 formed from glass or other suitable transparent insulating material. A. central passage 13 is formed in the 90 member 12 to provide a capillary tube. In the form shown in l, the upper end of the passage 13 is enlarged as at 14. Secured tothe cap 9 and projecting inwardly ofthe upper end of the passage 13 is a contact finger 15 which 95 serves as electric conductor. In the chamber 16 below the partition 11 is slidably positioned a piston 17 which may be moved axially of the chamber I6Y by means of the screw stem 18 threaded through the cap 8.

In use the caps 8 and 9 are engagedby suitable contact members in an electric circuit. These contact members are of a well known' type and are generally of a spring clip structure such as are now commonlyused for retaining car-Y 105 tridge fuses in a line. yThe chamber 16 is' lled with mercury or other suitable electric conducting liquid and by threading the stem 18` so as to force the pistonl'l toward the partition 11, the liquid in the compartment 16 will be forced 110 upwardly so as to iill the passage 13. Any overflow will be deposited in the compartment 16. It will be noted that the member 12 projects at its lower end below the bottom of the partition l1 so that the lower end of the member 12 is always immersed in the liquid below the upper surface thereof. Because of this structure the column of `liquid in the passage 13 will be substantially free from oxides and other impurities, which may rise to the surface of the liquid. When an overload comes on the line, the flash will Serve to break the column of liquid in the passage 13 and drive some of the liquid out of the passage 13 into the overflow chamber 16' either through a boiling operation or agitation. By projecting the contact finger 15 inwardly of the passage 13 compensation is made for shrinkage o! the liquid material in the passage 13. The back of the passage 13 may be coated with a phosphorescent paint so that the column of liquid in the passage 13 may be clearly seen from the exterior of the body 7. The member l! may also be formed at one side so as to magnii'y the column in the passage 13. After the fuse has "blown" the same may be restored to its operative position by further moving the piston 17 toward the partition 11 to force a new supply of liquid into the passage 13 so as to make the necessary contact.

The liquid in the overflow chamber 16' may be returned to the chamber 16 after expulsion of the liquid from the chamber 16.' This may be accomplished by inverting the body 7 and, while closing the hole 10 with the finger or the like, to prevent leakage, withdrawing the piston 1'7 from the partition 11 and thus drawing the liquid through the passage 13 into the supply chamber or reservoir `16. It will thus appear obvious that the life or the fuse is practically unlimited so that there is provided a permanent fuse in which all of the elements of safety which are desirable in a i'use are present.

In the form shownin Fig. 3 I have indicated the contact finger 15 projecting outwardly from the supporting rod 19 which extends inwardly from the inner surface of the cap 9'. It will belnoted that the inner end of the rod 19 overlies the end of the passage 13 and is but slightly spaced therefrom. This structure is quite adaptable for preventing a spilling of the liquid from the passage 13 through agitation. While the rod 19 must of necessity be slightly spaced from the end oi' the passage 13, the cohesive characteristics of the liquid which must be used are auch that under normal conditions the end of the rod 19 will prevent any dlslodgment of the liquid `intim the passage 13 which might otherwise take place.

In Fig. 4 I have shown the invention used with acrew plug 20 having the metallic screw shell 21 on its periphery which is adapted to thread into an electric socket. This shell 21 is provided with the extension strip 22 having the aiigularly turned end terminating in a retaining clip 24 adapted for clamping about one of the ends o! the fuse. A clip 25 is adapted to clamp about the other end of the fuse. This clip 25 is. formed on the strap 26 which terminates in the centrally positioned yieldable contact 27. In Fig. 5 I have shown a slightly different form of container in which the plug 25' is provided with the metallic threaded shell 21' from which projects :the arm 22' terminating in the metallic retaining clip 24' which is adapted to engage one end .01 the fuse. 'I'he opposite end is engaged by the clip 25 formed on the metallic strap 26' which terminates in the centrally positioned yieldable contact 27. With the retainers shown in Fig. 4 and in Fig. 5, the device may be used in all installations which are now established and installed in the same manner as the screw plug fuses commonly used. In newer types of installation, the spaced retaining clips may be provided such as are now provided for the conventional cartridge fuses. It is believed obvious that the advantages enumerated are to be found in the structure which I have described.

While I have illustrated and described the preferred form of structure of my invention, I do not wish to limit myself to the precise form of structure shown but desire to avail myself of such variations and modifications as may come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A fuse of the class described comprising: a receptacle having a partition therein dividing said receptacle into a pair of chambers; a tube having a narrow passage formed therethrough projecting into each of said chambers; means in one of said chambers for forcing the electric conducting liquid, contained in said chamber. into said passage for filling the same; an electric contact member contacting with the liquid in said chamber; and an electric contact member contacting with the liquid at the end of said tube in the other chamber.

2. A fuse of the class described comprising: a receptacle; a partition dividing said receptacle into a pair of chambers; a tube of non-conducting material having a narrow passage formed therethrough and projecting into each of said chambers so as to establish communication of said chambers with each other; a movable member in one of said chambers for forcing an electric conducting liquid, contained therein, therefrom into said passage for filling the same, the end of said tube projecting into said liquid below the normal level thereof; a contact member electrically connecting to the liquid in said chamber; and a contact member electrically connecting in the other chamber with the liquid in said tube.

3. A fuse of the class described comprising: a

receptacle; a partition dividing said receptacle into a pair of chambers; a tube of insulating material having a passage therethrough and having one end `projecting into one of said chambers, and the other end into the other of said chambers; a movable member in one of said chambers; means for moving said member at will for forcing an electric conducting liquid, contained in the chamber, from the chamber into said passage for lling the same; a contact A member electrically engaging the liquid in said chamber; and a contact member engaging in the other chamber the liquid in said tube.

4. A fuse of the class described comprising: a

receptacle adapted for the reception of electric i iio iso

iso

chamber for forcing the liquid into said passage.

5. A fuse of the class described comprising: a receptacle adapted for the reception of electric conducting liquid;`a partition dividing said receptacle into a pair of chambers, said liquid being normally contained in one of said chambers; a pair of spaced contacts on said receptacle, one of said contacts being normally constantly electrically connected to said liquid; a tube of insulation having a passage therethrough and having one end projecting into one of said chambers and the other into the other of said chambers, one end of said tube being normally immersed in the liquid; movable means for forcing the liquid from the liquid containing chamber into said passage; and stationary means carried by the other contact projecting into said passage and engaging the liquid therein.

6. A fuse of the class described comprising: a receptacle adapted for the reception of electric conducting liquid; a partition dividing said receptacle into apair of chambers, saidfliquid being normally contained in one of said chambers; a pair of spaced contacts on said receptacle, one of said contacts being normally constantly electrically connected to said liquid; a tube of insulation having a passage therethrough and having one end projecting into one of said chambers and the other into the other of said chambers, one end of said tube being normally immersed in the liquid; movable means for forcing the liquid from the liquid containing chamber into said passage; and stationary means carried by the other contact projecting into said passage and engaging the liquid therein, said means being enlarged exterior of said passage for resisting displacement of liquid from said passage through one end.

CLARENCE E. LEONARD. 

